The present invention relates generally to vehicle lock assemblies, and more particularly, to a vehicle lock assembly including a mounting bracket for mounting a cylinder lock on an exterior door, such as a deck lid or passenger door, and the like of a motor vehicle.
Cylinder locks are used on motor vehicles to secure rear deck lids or passenger doors and the like. The cylinder locks are key operated to release a latching mechanism that normally keeps the deck lid or passenger door closed and locked. Typically, the cylinder locks are mounted directly to a relatively thin exterior sheet metal panel which forms the exterior of a deck lid or a passenger door, for example. Although the locks are designed to resist compromising of the lock assembly itself, the application of force to the cylinder lock can cause the relatively thin sheet metal which supports the cylinder lock to bend and deform, displacing the lock relative to the latching mechanism which can result in unlatching of the deck lid or passenger door.
Various methods can be used in an attempt to compromise a vehicle lock system. One commonly used method is to insert a tool, such as a screw driver or other flat bladed instrument, into the key slot of the lock, and then lift or rotate the tool, thereby tilting or rotating the lock relative to the deck lid or passenger door on which the lock is mounted.
Because such vehicle locks generally are supported only by the relatively thin exterior sheet metal panel of the deck lid or passenger door, the application of a lifting force to the outer end of the cylinder lock can result in deforming of the exterior sheet metal, tilting the cylinder lock such that the inner end of the cylinder lock is moved downwardly. Many vehicle cylinder locks include a latch rod for coupling the lock cylinder to a latch release mechanism. When the inner end of the cylinder lock is moved downwardly, the latch rod is moved downwardly, operating the latch release mechanism, releasing a latching member from a lock bar or striker. Similarly, forcibly rotating the cylinder lock clockwise, for example, can cause the latch bar to be moved downwardly, releasing the latching mechanism.
A degree of anti-rotation protection for cylinder locks can be provided through the use of ribs projecting from the outer surface of the lock housing. The ribs are received in mating slots in the exterior sheet metal panel for anti-rotation purposes. However, when sufficient rotational force is applied to the lock cylinder, the projections will be forced out of the slots, or the sheet metal will be stripped. In either case, the forced rotation of the lock housing and lock cylinder will result in releasing of the latching mechanism.
A further consideration is the affect of vibration on motor vehicle cylinder locks. Testing has shown that when cylinder locks are mounted on an exterior sheet metal panel of a vehicle using standard mounting techniques, there will be excessive movement of the cylinder lock when the sheet metal panel on which the cylinder lock is mounted is subjected to vibration.
Thus, it would be desirable to have a cylinder lock assembly for deck lids and other exterior door locks of a motor vehicle that is more resistant to tampering and more immune to the effects of vibration, and which does not require a large number of additional parts, and which does not increase the number of steps in the assembly process to incorporate a cylinder lock stabilizing mechanism.
The disadvantages and limitations of the background art discussed above are overcome by the present invention. With this invention, there is provided a lock assembly for a motor vehicle having a sheet metal panel which normally closes an exterior opening of the vehicle. The lock assembly comprises a cylinder lock and a mounting bracket. The mounting bracket is adapted to mount the cylinder lock on a vehicle structure with the cylinder lock supported by the mounting bracket near a first end thereof and with a second end secured to the exterior sheet metal panel, located within an opening in the panel. The mounting bracket includes at least one mounting lug adapted to be fastened to the vehicle structure and a lock mounting portion adapted to support the cylinder lock near its second end, rearwardly of the exterior panel. The lock mounting portion defines mounting surfaces which cooperate with first and second indexing portions on the lock housing to support the cylinder lock and substantially prevent rotation of the cylinder lock relative to the mounting bracket and the sheet metal panel.
In one embodiment, the lock mounting portion includes first and second arms which project from a base portion of the mounting bracket and which define the mounting surfaces. In accordance with the invention, the lock housing is mounted on the mounting bracket in dovetail fashion to prevent the first and second arms from spreading apart if an attempt is made to forcibly rotate the cylinder lock. In addition, the mounting bracket itself is adapted to cooperate with the vehicle structure to resist forcible rotation of the lock.
It has been found that it is advantageous to provide some clearance between mating surfaces of the cylinder lock and the mounting bracket because that makes the cylinder lock assembly and the exterior sheet metal panel on which the cylinder lock is mounted less prone to destruction. Thus, a small gap is provided between mating surfaces of the cylinder lock and the mounting bracket to allow some give to resist deformation of the exterior sheet metal if an attempt is made to compromise the vehicle lock system.
Another important advantage of the invention is that installation of the mounting bracket does not require an additional step in the assembly process. The mounting bracket can be slid onto the cylinder lock along with a switch of the cylinder lock, as the switch is being installed on the cylinder lock. The mounting bracket is held in place by the switch while the switch is being secured to the cylinder lock. No additional process step is required because the mounting bracket is installed with the switch as a unit.